Molded electrical boxes designed for nail attachment to wooden beams or studs are well known in the industry. Molded electrical boxes with internal screw attachment are known in the prior art. U.S. Pat. No. 5,600,093 of Herth et al. describes such a dual purpose electrical box which is attached by two internal screws; it is especially convenient to use for old work. A pending application of Herth describes an electrical box for single fastener attachment using a single internal screw; for new work, two anti-rotation and positioning tabs are molded onto the mounting side of the box. The prior art does not reveal molded electrical boxes equipped with features permitting the three different types of attachment methods described above.